Spatial Distribution of Polyphenolic Compounds in Corn Grains (Zea mays L. var. Pioneer) Studied by Laser Confocal Microscopy and High-Resolution Mass Spectrometry

Flowered Grain Quality and Phytochemical Content of Non-Conventional Maize Hybrids from the Mexican Subtropics across Three Growing Cycles

Development of non-conventional hybrids responds to the demand for the Elotes Occidentales land-race for production of pozole. The effect of growing cycle (2019, 2020, and 2021) on physical characteristics, flowered grain quality, and phytochemical content of two non-conventional hybrids of pozolero maize, as well as the effect of the presence or absence of pedicel, type of pollination (open and controlled, 2019), and parents (female and male, 2020) on flowered grain quality and content of phytochemical compounds, were evaluated. Size, hardness, color, total phenols, and anthocyanins in unprocessed grain were determined. Yield, volume, and puncture force were measured in flowered grain. Results were analyzed with a factorial arrangement in a completely randomized design. There were significant differences (p ≤ 0.05) in most of the variables studied by effect of crop cycle and hybrid. Non-conventional hybrids had large grains (40 g 100 grains^-1), soft endosperm (flotation index > 60), pink-purple color, and phenol and anthocyanin contents similar to those reported for the Elotes Occidentales land-race. The presence or absence of the pedicel did not affect flowered grain quality. Controlled pollination favored anthocyanin synthesis. The female parent determined the anthocyanin content of non-conventional hybrids. Thermal processing reduced anthocyanins by 60%; however, they leached into the flowering broth, so that the pozole made from non-conventional hybrids can have improved nutraceutical value, relative to that of pozole made with Cacahuacintle land-race.

Autofluorescence-Based Investigation of Spatial Distribution of Phenolic Compounds in Soybeans Using Confocal Laser Microscopy and a High-Resolution Mass Spectrometric Approach

In this research, we present a detailed comparative analysis of the bioactive substances of soybean varieties k-11538 (Russia), k-11559 (Russia), k-569 (China), k-5367 (China), k-5373 (China), k-5586 (Sweden), and Primorskaya-86 (Russia) using an LSM 800 confocal laser microscope and an amaZon ion trap SL mass spectrometer. Laser microscopy made it possible to clarify in detail the spatial arrangement of the polyphenolic content of soybeans. Our results revealed that the phenolics of soybean are spatially located mainly in the seed coat and the outer layer of the cotyledon. High-performance liquid chromatography (HPLC) was used in combination with an amaZon SL BRUKER DALTONIKS ion trap (tandem mass spectrometry) to identify target analytes in soybean extracts. The results of initial studies revealed the presence of 63 compounds, and 45 of the target analytes were identified as polyphenolic compounds.

Identification and Spatial Distribution of Bioactive Compounds in Seeds Vigna unguiculata (L.) Walp. by Laser Microscopy and Tandem Mass Spectrometry

The research presents a comparative metabolomic study of extracts of Vigna unguiculata seed samples from the collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources. Analyzed samples related to different areas of use in agricultural production, belonging to different cultivar groups sesquipedalis (vegetable accessions) and unguiculata (grain accessions). Metabolome analysis was performed by liquid chromatography combined with ion trap mass spectrometry. Substances were localized in seeds using confocal and laser microscopy. As a result, 49 bioactive compounds were identified: flavonols, flavones, flavan-3-ols, anthocyanidin, phenolic acids, amino acids, monocarboxylic acids, aminobenzoic acids, fatty acids, lignans, carotenoid, sapogenins, steroids, etc. Steroidal alkaloids were identified in V. unguiculata seeds for the first time. The seed coat (palisade epidermis and parenchyma) is the richest in phenolic compounds. Comparison of seeds of varieties of different directions of use in terms of the number of bioactive substances identified revealed a significant superiority of vegetable accessions over grain ones in this indicator, 36 compounds were found in samples from cultivar group sesquipedalis, and 24 in unguiculata. The greatest variety of bioactive compounds was found in the vegetable accession k-640 from China.